【摘要】 分析了马先蒿属 (PedicularisL .)植物叶片稳定碳同位素组成 (δ13C值 )特征以及δ13C值与环境因子之间的关系 .结果表明 ,所有样品的δ13C值属于C3植物的范围 ,最大值是碎米蕨叶马先蒿 (Pedic ularischeilanthifoilia) ,- 2 2 .4‰ ,最小值属于黄花鸭首马先蒿 (Pedicularisanasvar .xanthantha) ,- 31.5‰ ,平均值为 - 2 7.1‰ .相关分析表明 ,马先蒿植物叶片的δ13C值与年降水量和湿润度的相关性没有达到显著水平 (P >0 0 5 ) ,与年平均温度和≥ 10℃的总积温呈显著负相关 (P <0 0 5 ) .随着海拔的升高 ,δ13C值增大 (P <0 0 5 ) ,与经度的变化呈负相关 (P <0 0 5 ) ,而与纬度呈现弱的正相关 (P <0 0 5 )关系 .更多还原

【Abstract】 There are two stable carbon isotopes in nature, {} 12C and {} 13C. During the process of photosynthesis, the heavier {} 13C isotope of atmospheric CO 2 is discriminated against the lighter {} 12C, because of differences in physical and chemical traits, leading to the poorer value of {} 13C/{} 12C in plant tissues, organs or chemical compositions. Most studies showed that δ 13C value in plant tissues reflects the effects of environmental factors on plant physiology and growth. In recent years, stable carbon isotope techniques were wide used in geography, ecology, genetics, agronomy and global change research. %Pedicularis% L. (Scrophularicaceae) has 500 species or more in the world, and near 400 of them are distributed in China. They favor the place with water, and thereby one can hypothesized that water status has a little impact on foliar δ 13C in the genus of %Pedicularis% L. other than environmental conditions, such as atmospheric CO 2 partial pressure, air temperature and effectively cumulative temperatures. To test this hypothesis, 47 species and/or samples were collected in 13 sites from Guyuan County of Ningxia Hui Autonomous Regions, Tianshan Mountains of Uygur Autonomous Region of Xinjiang, Zhouqu County, Luqu County, Maqu County, Diebu County, Yuzhong County, Subei County, Hezuo City, Minxian County, Chengxian County, Zhouni County, Tianzhu County and Xiahe County of Gansu Province. Foliar stable carbon isotope was measured with Mat-252, and correlative analysis was done between {δ 13}C and altitude, longitude, latitude, mean annual temperature, cumulative temperature of greater than 10 ℃, mean annual precipitation and humidity, respectively. Different δ 13C value was founded among species and sampling sites. The sample of %P. cheilanthifoilia% in Maqu County ({3 400} m a. s. l.) had the largest value ({-22.4‰}), and %P. anas% var. %xanthantha% from Zhuoni County ({2 500} m a. s. l.) was the least ({-31.5‰}), and the mean δ 13C values of all samples was {-27.1‰}. The relationship between δ 13C values and mean annual precipitation and humidity was not significant (%P%>0^05), δ 13C values of all sites had significantly relationship with mean annual temperature and cumulative temperature of greater than 10 ℃(%r%=0^34 and %r%=0^40,%P%<0^05). Foliar δ 13C values in Pedicularis sample obviously increased with increasing altitude and latitude, (%r%=0^37 and %r%=0^31, %P%<0^05); in contrast, δ 13C had negative relationship with longitude (%r%=0^29, %P%<0^05). The result supports the previous hypothesis, and indicates that photosynthetic capacity and temperature may play more important roles to affect the isotope composition of %Pedicularis%.更多还原